biology vs biological science

biology and biological science both are nouns.

Word	Noun	Adjective	Verb	Adverb
biology	Yes	No	No	No
biological science	Yes	No	No	No

As nouns, biology and biological science are synonyms defined as:

biology and biological science: the science that studies living organisms

biology (noun)	biological science (noun)
the science that studies living organisms	the science that studies living organisms
all the plant and animal life of a particular region
characteristic life processes and phenomena of living organisms